mirror of
https://git.do.srb2.org/STJr/UltimateZoneBuilder.git
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202 lines
4.9 KiB
C#
202 lines
4.9 KiB
C#
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#region ================== Copyright (c) 2007 Pascal vd Heiden
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/*
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* Copyright (c) 2007 Pascal vd Heiden, www.codeimp.com
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* This program is released under GNU General Public License
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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*/
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#endregion
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#region ================== Namespaces
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using System;
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using System.Collections;
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using System.Collections.Generic;
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using System.Globalization;
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using System.Text;
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using CodeImp.DoomBuilder.Geometry;
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using CodeImp.DoomBuilder.Rendering;
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using SlimDX.Direct3D9;
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using System.Drawing;
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using CodeImp.DoomBuilder.Map;
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#endregion
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namespace CodeImp.DoomBuilder.Geometry
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{
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public sealed class EarClipPolygon : LinkedList<EarClipVertex>
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{
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#region ================== Variables
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// Tree variables
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private List<EarClipPolygon> children;
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private bool inner;
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#endregion
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#region ================== Properties
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public List<EarClipPolygon> Children { get { return children; } }
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public bool Inner { get { return inner; } set { inner = value; } }
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#endregion
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#region ================== Constructors
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// Constructor
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internal EarClipPolygon()
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{
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// Initialize
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children = new List<EarClipPolygon>();
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}
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// Constructor
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internal EarClipPolygon(EarClipPolygon p, EarClipVertex add) : base(p)
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{
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// Initialize
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base.AddLast(add);
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children = new List<EarClipPolygon>();
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}
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#endregion
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#region ================== Methods
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// This merges a polygon into this one
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public void Add(EarClipPolygon p)
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{
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// Initialize
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foreach(EarClipVertex v in p) base.AddLast(v);
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}
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// This calculates the area
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public float CalculateArea()
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{
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// Multiply the x coordinate of each vertex by the y coordinate of the next vertex.
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// Multiply the y coordinate of each vertex by the x coordinate of the next vertex.
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// Subtract these.
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float result = 0.0f;
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int firstcalculated = 0;
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LinkedListNode<EarClipVertex> n1 = base.First;
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while(firstcalculated < 2)
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{
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LinkedListNode<EarClipVertex> n2 = n1.Next ?? base.First;
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float a = n1.Value.Position.x * n2.Value.Position.y;
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float b = n1.Value.Position.y * n2.Value.Position.x;
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result += a - b;
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n1 = n2;
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if(n2 == base.First) firstcalculated++;
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}
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return Math.Abs(result / 2.0f);
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}
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// This creates a bounding box from the outer polygon
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public RectangleF CreateBBox()
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{
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float left = float.MaxValue;
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float right = float.MinValue;
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float top = float.MaxValue;
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float bottom = float.MinValue;
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foreach(EarClipVertex v in this)
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{
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if(v.Position.x < left) left = v.Position.x;
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if(v.Position.x > right) right = v.Position.x;
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if(v.Position.y < top) top = v.Position.y;
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if(v.Position.y > bottom) bottom = v.Position.y;
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}
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return new RectangleF(left, top, right - left, bottom - top);
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}
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// Point inside the polygon?
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// See: http://local.wasp.uwa.edu.au/~pbourke/geometry/insidepoly/
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public bool Intersect(Vector2D p)
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{
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Vector2D v1 = base.Last.Value.Position;
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Vector2D v2;
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LinkedListNode<EarClipVertex> n = base.First;
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uint c = 0;
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// Go for all vertices
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while(n != null)
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{
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// Get next vertex
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v2 = n.Value.Position;
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// Determine min/max values
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float miny = Math.Min(v1.y, v2.y);
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float maxy = Math.Max(v1.y, v2.y);
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float maxx = Math.Max(v1.x, v2.x);
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// Check for intersection
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if((p.y > miny) && (p.y <= maxy))
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{
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if(p.x <= maxx)
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{
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if(v1.y != v2.y)
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{
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float xint = (p.y - v1.y) * (v2.x - v1.x) / (v2.y - v1.y) + v1.x;
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if((v1.x == v2.x) || (p.x <= xint)) c++;
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}
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}
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}
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// Move to next
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v1 = v2;
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n = n.Next;
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}
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// Inside this polygon?
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if((c & 0x00000001UL) != 0)
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{
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// Check if not inside the children
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foreach(EarClipPolygon child in children)
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{
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// Inside this child? Then it is not inside this polygon.
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if(child.Intersect(p)) return false;
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}
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// Inside polygon!
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return true;
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}
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else
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{
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// Not inside the polygon
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return false;
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}
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}
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// This inserts a polygon if it is a child of this one
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public bool InsertChild(EarClipPolygon p)
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{
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// Polygon must have at least 1 vertex
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if(p.Count == 0) return false;
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// Check if it can be inserted at a lower level
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foreach(EarClipPolygon child in children)
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{
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if(child.InsertChild(p)) return true;
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}
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// Check if it can be inserted here
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if(this.Intersect(p.First.Value.Position))
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{
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// Make the polygon the inverse of this one
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p.Inner = !inner;
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children.Add(p);
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return true;
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}
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// Can't insert it as a child
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return false;
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}
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#endregion
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}
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}
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